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Differential Equations/Nonlinear Analysis Seminar: Guillaume Carlier, CEREMADE, Université Paris-Dauphine, A refined Fenchel-Young inequality and applications to optimal transport and convex duality

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In this talk, I will first present a very simple quantitative form of the Young-Fenchel inequality.  I will then discuss some applications: a short proof of the Brøndsted-Rockafellar in Hilbert spaces and a primal-dual attainment for perturbed convex minimization problems. I will finally explain how this inequality (or some generalizations) can be used for quantitative…

Differential Equations/Nonlinear Analysis Seminar: Marco Antonio López Cerdá, Universidad de Alicante, A survey of the subdifferential of the supremum function. Featured applications

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his talk presents various characterizations of the subdifferential of the pointwise supremum of an arbitrary family of convex functions, as well as some featured applications. Starting by the maximum generality framework, we move after to particular contexts in which some continuity and compacity assumptions are either imposed or inforced via processes of compactification of the…

Nonlinear Analysis Seminar and Differential Equation Seminar: Ayman Rimah Said, Duke University, Logarithmic spirals in 2d perfect fluids

SAS 4201

In this talk I will present recent results with In-Jeong from Seoul national university where we study logarithmic spiraling solutions to the 2d incompressible Euler equations which solve a nonlinear transport system on $\mathbb{S}$. We show that this system is locally well-posed in $L^p, p\geq 1$ as well as for atomic measures, that is logarithmic…

Nonlinear Analysis Seminar and Differential Equation Seminar: Mihaela Ifrim, University of Wisconsin Madison, Global solutions for 1D cubic defocusing dispersive equations: Part I

SAS 4201

This article is devoted to a general class of one dimensional NLS problems with a cubic nonlinearity. The question of obtaining scattering, global in time solutions for such problems has attracted a lot of attention in recent years, and many global well-posedness results have been proved for a number of models under the assumption that…

Nonlinear Analysis Seminar and Differential Equation Seminar: Mikhail Perepelitsa, University of Houston, Kinetic modeling of Myxobacteria motion with nematic alignment

SAS 4201

Motivated by motion of myxobacteria, we review several kinetic approaches for modeling motion of self-propelled, interacting rods. We will focus on collisional models of Boltzmann type and discuss the derivation of the governing equations, the range of their validity, and present some analytical and numerical results. We will show that collisional models have a natural…

Nonlinear Analysis Seminar and Differential Equation Seminar: Fabio Ancona, University of Padova, Italy, Hard congestion limit of the p-system in the BV setting

SAS 4201

We are concerned with the rigorous justification of the  so-called hard congestion limit from a compressible system with singular pressure towards a mixed  compressible-incompressible system modeling partially congested dynamics, in the framework of BV solutions. We will consider small BV perturbations of reference solutions constituted by (possibly interacting) large interfaces, and we will  analyze the dynamics of…

Nonlinear Analysis Seminar and Differential Equation Seminar: Liviu Ignat, Institute of Mathematics, Simion Stoilow of the Romanian Academy, Romania, Asymptotic behavior of solutions for some diffusion problems on metric graphs

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In this talk we present some recent result about the long time behavior of the solutions for some diffusion processes on a metric graph.  We study  evolution problems on a metric connected finite graph in which some of the edges have infinity length. We show that the asymptotic behaviour of the solutions of the heat…

Nonlinear Analysis Seminar and Differential Equation Seminar: Shaoming Guo, University of Wisconsin Madison, Oscillatory integral operators on manifolds and related Kakeya and Nikodym problems

SAS 4201

The talk is about oscillatory integral operators on manifolds.  Manifolds of constant sectional curvatures are particularly interesting, and we will see that very good estimates on these manifolds can be expected. We will also discuss Kakeya and Nikodym problems on general manifolds, in particular, manifolds satisfying Sogge’s chaotic curvatures.

Nonlinear Analysis Seminar and Differential Equation Seminar: Weinan Wang, University of Oklahoma, Global well-posedness and the stabilization phenomenon for some two-dimensional fluid equations

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In this talk, I will talk about some recent well-posedness and stability results for several fluid models in 2D. More precisely, I will discuss the global well-posedness for the 2D Boussinesq equations with fractional dissipation. For the Oldroyd-B model, we show that small smooth data lead to global and stable solutions. When Navier-Stokes is coupled…

Nonlinear Analysis Seminar and Differential Equation Seminar: Eduardo Casas Renteria, University of Cantabria, Second Order Analysis for Optimal Control Problems

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In this talk, we discuss second-order optimality conditions for optimal control problems. This analysis is very important when we study the stability of the solution to the control problem with respect to small perturbations of the data. It is also crucial for proving superlinear or quadratic convergence of numerical algorithms for solving the problem, as…

Nonlinear Analysis Seminar and Differential Equation Seminar:Giuseppe Buttazzo, University of Pisa, Italy, Antagonistic cost functionals in shape optimization

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In several shape optimization problems one has to deal with cost functionals of the form ${\cal F}(\Omega)=F(\Omega)+kG(\Omega)$, where $F$ and $G$ are two shape functionals with a different monotonicity behavior and $\Omega$ varies in the class of domains with prescribed measure. In particular, the cost functional ${\cal F}(\Omega)$ is not monotone with respect to $\Omega$…

Nonlinear Analysis Seminar and Differential Equation Seminar: Leon Bungert, University of Würzburg, Adversarial robustness in machine learning: from worst-case to probabilistic

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In this talk I will first review recent results which characterize adversarial training (AT) of binary classifiers as nonlocal perimeter regularization. Then I will speak about a probabilistic generalization of AT which also admits such a geometric interpretation, albeit with a different nonlocal perimeter. Using suitable relaxations one can prove the existence of solutions for…

Nonlinear Analysis Seminar and Differential Equation Seminar: Tu Nguyen Thai Son, Michigan State University, Generalized convergence of solutions for nonlinear Hamilton-Jacobi equations

SAS 4201

We examine the asymptotic behaviors of solutions to Hamilton-Jacobi equations while varying the underlying domains. We establish a connection between the convergence of these solutions and the regularity of the additive eigenvalues in relation to the domains. To accomplish this, we introduce a framework based on Mather measures that enables us to compute the one-sided derivative…

Nonlinear Analysis Seminar and Differential Equation Seminar: Anna Doubova, University of Seville, Inverse problems connected with Burgers equation and some related systems

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We consider inverse problems concerning the one-dimensional viscous Burgers equation and some related nonlinear systems (involving heat effects, variable density, and fluid-solid interaction). We are dealing with inverse problems in which the goal is to find the size of the spatial interval from some appropriate boundary observations. Depending on the properties of the initial and…

Nonlinear Analysis Seminar and Differential Equation Seminar: : Benjamin Seeger, University of Texas at Austin, Weak solutions of nonlinear, nonconservative transport systems

SAS 4201

I will discuss certain systems of transport type whose coefficients depend nonlinearly on the solution. Applications of such systems range from the modeling of pressure-less gases to the study of mean field games in a discrete state space. I will identify a notion of weak solution within the class of coordinate-wise decreasing functions, a condition…

Nonlinear Analysis Seminar and Differential Equation Seminar: Nicolás García Trillos, University of Wisconsin Madison

SAS 4201

Despite the success of deep learning-based algorithms, it is widely known that neural networks may fail to be robust to adversarial perturbations of data. In response to this, a popular paradigm that has been developed to enforce robustness of learning models is adversarial training (AT), but this paradigm introduces many computational and theoretical difficulties. Recent…

Nonlinear Analysis Seminar and Differential Equation Seminar: Thierry Champion, University of Toulon, France,Relaxed multi-marginal costs in optimal transport and quantization effects

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 In this talk, I shall present a relaxation formula and duality theory for the multi-marginal Coulomb cost that appears in optimal transport problems arising in Density Functional Theory. The related optimization problems involve probabilities on the entire space and, as minimizing sequences may lose mass at infinity, it is natural to expect relaxed solutions which…